This is a scale case for a 5kg scale Module and the HX711 pcb.

It can be connected to a RaspberryPI and used by the Octoprint Plugin “Filament Scale Enhanced” (https://plugins.octoprint.org/plugins/filament_scale/)

The filament spool holder can be set on top. Like this one from Copanko: 

Spool holder for Prusa MINI Flexible

 

Wiring should be like this:

Raspi HX711 Scale Modul VCC 5V ----- VCC | A+ ----- green GND ----- GND | A- ----- white SCK (Clock) GPIO20 ----- SCK | E- ----- black (GND) DO (Data) GPIO21 ----- CO | E+ ----- red (VCC)

Scale modul and HX711 can be found on e.g.  Amazon or cheeper on AliExpress

You also need 4 M4x16 screws to mount the scale module. You can use 2mm thick foam rubber (4x 14x16x2mm) as soft feets.